I attended four climate change sessions at Aussiecon 4, two of them I wrote about in my last Aussiecon post.
Designer Planet: Averting Climate Change with Geoengineering.
This session was conducted solo by science fiction author Gregory Benford. He is also an astrophysicist in the Department of Physics and Astronomy at the University of California, Irvine. I have read a number of his novels including the excellent 1980 Nebula Award winner Timescape.
During the talk he gave out his email address so people could request further information, I did so. He emailed back a number of articles including two which comprised much of what he said during his talk, and an excellent article Prozac for the Planet by Christopher Cokinos, about a geoengineering conference which he attended.
Gregory Benford started by telling us that greenhouse gases make up 388 parts per million of the atmosphere, and that is increasing by 3ppm per year. (Currently world attempts focus on keeping it below 450 ppm, which would cause an expected 2 degrees Celsius average global temperature increase).
He says after us pumping 200 years of CO2 into the atmosphere, a ½ metre rise in oceans is inevitable.
He said that no economist he knew thought we could replace our current energy sources with renewables in less than 50 years, so we have to find other means of fighting global warming. He seemed very doubtful about the planet’s governments getting their act together and reducing our greenhouse gas output to anything near what was required.
He dismissed space based reflection of sunlight back into space as it would cost about three trillion dollars.
One surprising point he mentioned is that while tropical countries clear their rain forests, the temperate nations have been growing more trees, with tree coverage rebounding in the US after 1950.
He thought about half the US CO2 emissions could be captured if the US grew tree crops on economically marginal croplands. In the short term this would work, but we would soon run out of land. Soaking up the world’s present CO2 increase would take tree planting over a country the size of Australia. But trees absorb more sunlight than grasslands, so they might increase warming in the long run.
This left other advanced technological paths to global climate stability.
· Renewable energy, but it has a high capital cost.
· Burying crops in oceans
· Magnesium carbonate bricks
· Pumping liquid CO2 to the bottom of the ocean
He said that 4-6 pg of CO2 accumulates every year. He estimates that the cost of removing that CO2 10 trillion dollars per year
He had had conducted an experiment on one way of reducing the level of CO2 in the atmosphere. Many crops leave an unused residue of 30% of the crop. This residue could be bundled together and floated down rivers on barges and then dropped into the ocean, below the ocean’s thermocline so the carbon it released stayed in the oceans for at least a thousand years. This method could account for about 13% of the total US carbon emissions in 1990. Acidification of the oceans is occurring in the top km, so the bundles would be sank much further down.
He said this method operated at a 92% efficiency. Whereas turning crops into ethanol only had a 32% efficiency.
He then suggested a way of geoengineering the planet to reflect sunlight back into space. He said we could compensate for the effect of all the greenhouse gases since the industrial revolution if we reflected one percent of the sun’s light. This would solve the greenhouse effect for many decades.
The best way to reflect the sun’s rays would be by spreading dust or droplets of sulfuric acid into the stratosphere. Tiny particles stay aloft for several years. According to his notes “the amount of droplets or dust needed is at most ten times smaller than the amount already blown into the atmosphere by natural processes.”
But there are possible side effects such as the ozone layer being affected.
So he suggested an experiment should be conducted over the Arctic. He thought this might gain ground because the US, like Russia, hides its subs under the Arctic, so the military might be agreeable to an experiment that prevented the sea ice from melting. He said that the KC10 extender plane, airforce mid-air refuelling jets, that are just about to be retired, could be used to spread the dust. He suggested it would cost about 2-3 billion dollars to screen the Arctic for a year.
“Ken Caldiera, who holds the chair at the Carnegie Institute at Stanford University has modelled the idea of Arctic cooling…his preliminary findings show that a full scale program of adding aerosols at stratospheric levels could restore the Arctic within a few years.”
More sea ice means less dark sea and more reflection of sunlight.
I was not too sure what would happen after a successful experiment. I got the impression that cooling the Arctic substantially, might slow global warming over the entire planet. But, as Gregory said, we can’t just keep pumping aerosols into the stratosphere to combat a continual increase in greenhouse gases, the oceans would become more acid, and a disaster could happen if the aerosols failed, leading to a sudden increase in temperatures. He sees the spraying of aerosols into the stratosphere as a measure to stall climate change and give us more time to reduce the output of greenhouse gases.
I left the session a bit more hopeful for civilisation, as geoengineering the planet might be a solution to our political unwillingness to do anything substantial about climate change.
Climate Change: Possible Futures for Planet Earth. 
Authors Kim Stanley Robinson and Sean McMullen, moderator Grace Duncan, an exhausted science communicator Tiki Swain and environmental scientist Jonathon Cowie.
I had heard much of what Jonathon Cowie and Kim Stanley Robinson had to say in previous sessions on climate change. Jonathon reiterated some of the science, Kim, stressed the need to use all possible greenhouse gas reduction methods, like reverting to sailing ships and using a combination of organic and genetically engineered food production.
Sean McMullen stressed that we had to change our values, to use less energy. He had gone from living in a 17 room mansion to a two bedroom flat. He hoped there would be less food wastage. He felt the soft underbelly of reducing greenhouse gases was reducing waste.
Tiki hoped there would be more emphasis on the sharing of resources, ie, the sharing of farm machinery between farmers.
Personally, I think we should try everything including nuclear power, genetic engineering, banning air travel in favour of large sailing ships and teleconferencing, and geoengineering, and start implementing it now.
I grow a lot of my own veggies and fruit. We installed a solar hot water panel last year. This year we got rid of the old gas heater and installed a thermostatically controlled one. Not only did doing the above decrease my greenhouse gas output but it saves us money. Energy prices are only going to keep on going up. I don’t own a car and walk everywhere, even though I live in the country. Walking gives me time to think, about writing, about climate change, about the future of humanity.
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